Roller bit



June 18, 1940. c, BRENDE'L 2,204,657.

ROLLER BIT Filed July 12, 1958' INVENTOR. C(yoo 15/12? 08 WwM ATTORNEY.

Patented June 18, 1940 Q r UNITED STATES PATENT OFFICE ROLLER BIT Clyde Brendel, Los Angeles, Calif.

Application July 12, 1il38, Serial No.218,810

4 Claims. (01. 255-411) I This invention relates to a roller bit, and more Figure 4 is a perspective view of the structure particularly to a type of bit carrying a plurality used for supporting the cross cutter rollers.

of. cutters for removing the formation at the I The roller bit includes a main body or shank bottom of the hole. portion I having a tapered threaded pin 2 at its It is an object. of this invention to provide a upper end whereby the bit can be rotated from 5 roller bit that can be readily assembled, and still the surface of the bore through the usual drillbe of sturdy construction in its entirety and in ing string .(not shown), or turned by other. suitits component parts. able mechanisms, as a multi-stage hydraulic tur- Another object of the invention is to simplify bine (not shown) positioned in the drilling string 1;, the construction and manufacture of roller bits, above the bit. The main body portion also carespecially those including cross cutter rollers, ries cross cutter rollers 3, 3' which will remove which serve to cut the major portion of the bore, the major portion 3a of the formation material, and side cutter rollers, which are designed to and also side cutter rollers, 4, 4 that are adapted cut the outer portions of the bore and maintain to remove the outer portions 4a of the bore diam the hole to gauge. eter and maintain the hole to gauge. These cut- 15 Another object of the invention is to so arrange ters are suitably mounted for rotation about their and support the cross cutter rollers of. a roller own respective axes, being provided with approbit as to leave substantially no core at the axis priately shaped teeth, which in the present inof the hole produced. stance are of. generally V-shape, although it is A further object of the invention involves a to be' understood that various other shapes and 20 roller bit having cutters and bearing supporting designs of teeth can be used in place of the speparts which can be easily assembled to the main cific forms disclosed. The side cutter rollers 4, body of the bit, and also readily demountedthere- 4' have the back portions 5 of their teeth enfrom with substantially no effect upon the main gageable with the walls of the hole to determine body portion, in order that the cutters, bearings, the final diameter of bore produced by the bit. 25

- and bearing supporting parts can be replaced. The effective life of each tooth is preferably in- Still another object of the invention is .to procreased by hardfacing one or more of. its cutting vide a roller bit having cutters that are adjustsurfaces in a well-known manner, as by the use able .to produce various bore hole sizes or of welded on tungsten carbide. diameters. The cross cutter rollers 3, 3' are carried by a 30 Another object of the invention is to provide unitary supporting structure 6 having an upper a roller bit having cutters that are adjustable to face plate I and three depending legs 8, 9, I0. produce various bore hole sizes or diameters, and Each of the legs is provided with a bore H, I2 or in which the cutters are properly locked in their [3 through which extends a single bearing supparticular positions of adjustment. porting shaft i4, suitably held in place by weld- 35 The present invention has other objects and ing material l5 attaching the end portions of the advantages which will-become apparent from a shaft to the sides of the bores ii and I3 in the consideration of one embodiment of. the invenend legs 8 and It so that the shaft is prevented, tion, which is shown in the drawingaccompanyfrom rotating and moving axially while the drilling and forming part of the present specification. ing tool is in operation. v 40 Although this particular form will now be del The shaft l4 serves as an external raceway for scribed in detail to illustrate the general princia plurality of bearings l6, preferably of the roller ples of the invention, it is to be understood that type, which contact also with the internal racethe invention is not limited to the specific details ways ll, ll provided in the respective cross cutdisclosed, but covers all variations, modifications, ters 3, 3'. The rollerv bearing construction de- 45 and adaptations falling within the scope of the scribed will serve to transmit to the bearing supappended claims. l v porting shaft the radial loads imposed by the In the drawing formation upon the cutters. End thrusts, or axial Figure 1 is an elevation partly in section of a loads, aretransmittable through the respective 50 roller bit embodying the present invention. thrust bearings l8, l8 each of which preferably Figure 2 is a sectional view of the bit, taken consists of a ball race i8a bearing against one along the plane 2-2 of Figure 1. 'ofthe end legs 8 or ill, a second ball race 18b Figure 3 is an elevation of. the bit as seen from abutting a cross cutter with the thrusts or loads the rightof Figure 1, and passing from the cross cutters to the end legs 55 through the intermediate balls I80 engageable with both races. Each cross cutter is preferably recessed to receive and encompass its bearing.

While substantially the entire end thrust will be directed outwardly through the thrust bearings IB, I8, any inwardly directed end thrusts will be absorbed by the engagement of the inner end portions IQ of the cross cutter rollers with the intermediate leg 9. These portions preferably extend inwardly to the bearing shaft I4 to limit the extent of axial movement of the rollers I6 and confine them in operative position.

Each of the side cutter rollers 4, 4' is mounted upon an arm 20 having a bearing supporting member 2| extending inwardly therefrom. Radial loads are preferably transmitted from the cutter to the bearing support through the rollers 22 moving on the outer cylindrical raceway 23 on the bearing supporting member and the inner cylindrical raceway 24 in the cutter. outwardly directed end thrusts are transmitted through bearing balls 25 riding in the toric raceway 26 in the end face of the bearing supporting member and'in a corresponding raceway 21 provided in each cutter. Each cutter is maintained in assembly on its bearings by means of the pin 28 threadedly or otherwise receivd in a bore 29 in the arm 20, the pin having a. large head 28a bearing against the inner end surface of the cutter and preferably seated within a recess 28b. Assurance is made that the pin will not be removed through the use of welding material 30 fastening its outer threaded end portion to the side walls of the bore 29 in the depending arm. This headed pin, in addition to holding the cutter and bearing parts in assembly, will also resist inwardly directed end thrusts imposed by the sides of the bore upon the side cutters. 4

The cross cutters 3, 3' can be assembled to their supporting structure 6 by placing the ball and roller bearings |8, IS in the bores provided in each cutter, and then inserting the cutters containing the bearings between the legs 8, 9, ll) of the supporting structure with the cutter bores in alignment with the holes l2, l3 in the legs. The bearing supporting shaft H can then be inserted through the legs and cutter bores beginning with one of the end legs 8 or ID. The welding of the end portions of the shaft as heretofore described will insure that the parts will be held in assembled relationship.

In a similar manner, the rollers and balls 22, 25 can be placed on the respective raceways of the side cutter bearingsupporting members 2|, and the cutters 4, 4' placed thereover with the rollers and balls engaging the cutter raceways.

After assembling the cutters to their respective supporting structures, such parts are fixed to the main shank body primarily through the use of welded material. The undersurface of the main body is preferably a plane la, and the upper surfaces Ia, 20a. of the cross cutter supporting plate 1 and the side cutter supporting arms 20 are correspondingly fiat or plane so as to contact snugly therewith when the parts are placed together. Such assemblyis accomplished by grouping the various supporting members approximately in the relative positions they will occupy when attached to the main body portion. That is, the side cutter supports are disposed approxi- Adequate securement of the cross cutter supporting member 6 to the main body portion is obtained through beveling or scarfing the plate around its entire perimeter and building up welding material 36 in the groove thus produced between the beveled plate portion and the plane surface la of the shank to produce a substantially rigid and integral connection between the shank I and the cross cutter supporting structure 6. Similarly, the upper portions of the-side cutter supporting arms 20 are beveled or scarfed for the deposition of welding material 31 in the groove formed with the shank. This weld will likewise extend almost entirely around the arms.

Due to the inclined axis about which the side cutter rollers 4, 4' are rotatable, the inner surface 20b ofthe arms 20 can be inclined upwardly and inwardly. This arrangement will permit an overlap to be achieved between the cross cutter supporting member and thearms, which overlap can result from the bevelr'lb initially formed on the cross cutter plate 1. Additional attachment and integration of the arms and plate can be had by welding in the fillet 38 between the undersurface ,35 of the plate and .the respective inclined surfaces 20b of the arms 20,

The arms supporting the side cutters 4, 4 can be assembled in various definite positions of adjustment'with-regard to the main body portion so that the same parts can be used to provide a drilling bit capable of producing a limited range of bore hole sizes or diameters. In the specific form disclosed in the drawing, the upper portion of each arm is provided with a preferably cylindrical recess v39 which can accommodate an eccentric head 40 made integral with, or otherwise secured to, an eccentric shaft 4| which can fit within a hole 42 provided in the main body of the drilling tool. with an offset m with respect to the center line of the shaft 4|. By turning the shaft 4| relative to the arm20, it is apparent that a range of adjustment or movement of the side cutters 4, 4' transversely of the bit axis can be had equal to twice the distance of the offset, or 2.1:. The teeth on the side cutters are of sufiicient length to overlap the path 3a traced by the cross cutters, so that the adjustment of the side cutters outwardly to the maximum extent will still leave no gap between the paths traced by the side cutters and cross cutters. I

The necessary adjustment for diameter can be made justprior to the welding of the side cutter arms to the main body of the bit simply by turning the eccentric shafts 4|, whichwill effect an inward or outward movement of the arms and cutters until the desired effective bit diameter is obtained. The upper arm portions could then be tacked by welding to hold the adjustment obtained, after which the entire portion around the arms could be welded, as previously described.

However, it is preferred to fix the position of each eccentric 40 within the bore 39in its cooperating arm prior to assembly" of "the various The eccentric 40 is provided parts to the main body portion. To achieve this purpose, the eccentric head is provided with a plurality of circumferentlally spaced notches Ila which can seat the conical end of a set screw 43 threaded into a bore 44 provided in the outer face of each arm. The turning of the eccentric to various angular positions in the bore 30 will finally determine the position of the side cutters when the arms 24 are attached to the main shank portion of the bit, and consequently, the bore hole size produced. In the position shown in Figure 1 the eccentric is so adjusted as to provide a minimum bore size diameter, the set screw 43 seating within one of the notches 40a. Prior to assembly of the arm to the shank, if the eccentric were turned 180 degrees and the set screw then inserted in the opposite notch, a'maximum bore diameter would be obtained for the particu lar eccentric throw being used. {Turning of the eccentric to various intermediate positions would provide correspondingly intermediate side cutter adjustments and produce intermediate bore diameters. Once the eccentric has been properly positioned in its bore and held in position by the set screw, the particular side cutter supporting arm, eccentric, and eccentric shaft can be assembled to the shank by placing the shaft within the shank hole 42 and welding the arm 20 to the main body I as described. If'deemed essential, removal of each set screw can be prevented by welding its head to the arm 20.

It is the desirability of providing the overapping relationship and eccentric side cutter nounting which requires that the various sup- Jorting parts for the cutters be placed against ;he plane surface of the shank in substantially heir proper assembled relationship prior to the milding up of the welded material in'the grc eves )etween the shank I, plate I, and upper.supportng arm portions. Otherwise, the need for in- :erting the eccentric shafts into the shank bores vould conflict with the requirement that the in- :lined arm faces 24b be overlapped by the bevels b on the plate I.

Although not essential to the maintenance of he side cutters in adjusted position, the upper and of the eccentric shaft H is preferably fixed achment can be maoe simply by welding the and of the shaft to the sides of the bore '42 which eceives it. However, it is preferred" to use the welded arrangement now to be described.

It is customary to provide roller bits with eamer cutters 45 on the tapered portions 46 exending between the upper pin 2 and the outercost body portions, in order that the bit can drill ts way out in the event the formation'caves into he hole being produced. In the present instance, he reamer blade 45 is designed to function as a ack for the eccentric shaft in addition to its ordilary function. This purpose is achieved by proiding a blade having the usual outer cutting dges with its inner portion 45a stepped to fit rithin the bore 42 receiving the eccentric shaft I and in close proximity or engageable with the mper end of this shaft. The reamer blade is uitably scarfed or beveled, builtup welding maerlal rigidly integrating it with the main body of he hit and also with the eccentric shaft. The relded attachment between the shaft and reamer lade not only serves to lock the eccentric shaft a adjusted position, but also aids in the support I the side cutter arms, acting-throughthe set crew 43. Since two eccentric shafts are used, at east two reamer'blades can be provided on opposite sides of the bit, although this member can be increased.

The .drilling tool is kept clean and the cuttings removed from the bottom of the hole by circulating fluid through the drilling 'string (not shown) and then through the passageway 41 provided in the main body of the bit. The cross cutter support I is provided with two flaring discharge nozzles 48', 48 communicating with the passageway to direct drilling mud or. other fluid onto the cross cutters to clean them of adhering matter. The side cutters are kept clean by fluid discharging through the holes 4!, 49 in the cross cutter support, which holes communicate likewise with the internal passageway 41 in the main body of the bit.

To eliminate the core that usually remains at the axis of the bore, the intermediate depending leg 9 is offset to one side of the'center line of the bit so that one of the cross cutters 3 can extend to the hole axis. In performing its cutting action on the bottom of the hole this cutter will insure that the central portion of the bore material is removed by its cutting teeth, rather than requiring it to be broken away by non-cutting portions of the bit. Drilling progress of the tool is thereby increased.

The bit structure described can have its cutting elementsreplaced, eliminating the need for discarding the entire tool after a run has been made. Only those parts need be eliminated that are worn. As it is usual for the main body portion I to receive practically no wear during use of the bit, it can be used for a number of runs. In the instant case, the various welds 36, 31 integrating the cross cutter support and side cutter arms with the main body of the bit can be burned away through the use of a suitable cutting torch or carbon pencil. Similar cutting away of the welds binding the eccentric shafts H to the reamer cutters 45 and removal of the screws 3| holding the plate to the shank will permit the entire lower portion of the bit to be removed from the main body portion I. In removing the welds, substantially no damage is done to the main body portion, permitting its use with another assembly at a savings in material and expense. vith respect to the main body of the bit. At-

Usually, the cross cutter support 6 and the side cutter arms 20 can be used over again, their respective cutters 3, 3', 4, 4' being easily replaceable. The side cutters can be removed by burning away the weld 30 or by drilling it out on a suitable drill press. The threaded pin 28 can then be unscrewed to allow removal of the side cutter and its replacement by a new one, the pin then being reinserted and rewelded to the arm. In a similar manner, the welds l at the ends of the cross cutter main bearing shaft [4 can be burned away or drilled out, allowing this shaft to'be moved endwise from the cross cutter support and the cutters taken from their positions tiguous said main body surface, and a plurality of depending legs, an arm on each side of said structure, each arm having a plane surface contiguous said main body surface, means for securing said structure and arms to said main body in the 75 region of said contiguous surfaces, and roller cutters rotatably carried by said legs and arms. 2. A drill bit including a main body having a single plane surface at its lower end, a support- 5 ing structure having a plane surface contiguous said main body surface, an arm at each side of said structure the inner faces of said arms being overlapped by said structure which extends beyond the ends of said inner faces, each arm having a plane surface contiguous said main body surface, said structure and arms being welded to said main body in the region of said contiguous surfaces, and roller cutters rotatably carried by said structure and arms.

3. A drill bit as defined in claim 2; the overlapping portions of said structure and arms being welded together.

4. A drill bit including a main body, a supporting structure welded to said body, an. arm on each side of said structure welded to said body, each arm having an inner surface inclinedupwardly and inwardly, said structure overlapping and engaging the inclined arm surfaces, and roller cutters rotatably carried by said structure and arms.

,5. A drill bit including a main body having aplane surfaceat its lower end, a unitary supporting structure having a plane surface con 'tiguous said main body surface, an arm on each surface contiguous said main body surface, means for securing said structure and arms to said main body in the region of said contiguous surfaces, said structure including a plurality of depending 35 legs, cross cutter rollers rotatably carried by said legs, and side cutter rollers rotatably carried by said arms.

' 6. A drill bit including a main body having a plane surface at its lower end, a supporting structure having a plane surface contiguous said main body surface, an arm on each side of said structure, each arm having a plane surface contiguous said main body surface, means for securing said structure and arms to said main body 4' in the regionof said contiguous surfaces, said structure including a pair of depending and legs and an intermediate leg, a pair of cross cutter rollers each rotatably carried between an end leg and said intermediate leg, and roller cutters rotatably carried by said arms.

7. A drill bit as defined in claim. 6, said intermediate leg being oll'set with respect to the axis of the bit, whereby one of said cross cutter rollers can extend to said axis. I r

8. A drill bit including a main bodyxa sup-- porting structure attached thereto, said structure having a pair of depending end legs andan intermediate leg, a roller cutter rotatably mount- 4 ed between and carriedby each end leg and said intermediate leg, said intermediate leg being offset'with respect to the axisof the bit, whereby one/of said cutters can extend to said axis.

' side of said structure, each arm'having a plane 9. A drill bit includinga main b dy. a support attached thereto, a roller cutter rotatably carried by said support, and adjustable means-within said support and cooperable with said body,

said adjustable means being movable to various positions of adjustment while retained in said support, whereby the generally radial position of said support with respect to said body can be varied 10. A drill bit including a main body, a support attached thereto, a roller cutter rotatably carried by said support, adjustable eccentric means within said support, a shaft within said body fixed to said eccentric means, and means for locking said eccentric means and shaft in variin the region of said surfaces, a roller cutter rotatably moimted on'said support, an eccentric within said support, a shaft within a bore in said.

body fixed to said eccentric, and means for locking said eccentric and shaft in various, positions of adjustment to determine the position of said support with respect to said body.

13. A drill bit including a main body, a support attached thereto, a roller cutter rotatably carried by said support, adjustable eccentric means within said support. a shaft within said body fixed to said eccentric means, and a reamer' fixed to said body and shaft to lock said eccentric means .in selected positions of adjustment.

14. A drill bit including a main body having a single plane surface at its lower end, a supporting structure having a plane surface contiguous said main body surface, an armcn each side of said structure, each arm having a plane surface contiguous said main body surface, said structure and arms being welded to said main body in the region of said surfaces, said struc ture including a plurality of depending legs, cross cutter rollers rotatably carried by said legs, side cutter rollers rotatably carried .by said arms, an

eccentric within each arm, a shaft fixed to each eccentric, each "shaft fitting within said main body, said eccentrics being adjustable whereby the transverse-positions of said side cutter rollers can be varied.

' CLYDE BRENDEL. 

